Account incorrectly recorded as defaulted.

I had an account with MTN (account number A***) which is recorded in my credit record as having defaulted. I have liaised with MTN to resolve this issue. MTN forwarded an email to the bureau clearly stating that my account is paid off and has never been handed over. When I checked my credit record a couple of days ago I found that Experian has not removed a default flag even though they were requested by MTN. My Experian CIN number ***.